1. Field of Invention
This invention relates to bulk containers for the shipping and storage of liquids and dry powders. In particular, it relates to such containers as have dispensing valves and are reusable.
2. Description of Related Art
Many liquids and dry powders used in large quantities in manufacturing operations are transported in what are called bulk containers. Barrels and drums are examples of these. Often it is desirable to be able to quickly and easily draw off just a portion of the container's contents. For this purpose, the container can be equipped with a dispensing device, e.g., a gravity flow valve near the bottom of the container.
Bulk containers larger than the traditional fifty (50) or fifty-five (55) gallon metal drums have grown in popularity in recent years. Thus, for example, blow-molded plastic bottles ranging in size from about thirty (30) to one thousand (1,000) gallons are now in widespread use. Generally, these bottles are held inside wooden or metal crates or boxes, or inside multi-walled, corrugated paper boxes, to allow them to be stacked one atop the other, even when full, and to protect them against puncture. After these bottles are empty, however, it is very difficult to clean them out so that they can be reused. Usually, these bottles are scrapped after one use. Corrugated paper outer boxes are invariably weakened during use and have to be scrapped after one use as well.
The cost of disposing of such containers is significant. Environmental regulations prohibit burying them intact in landfills. They must be broken down first, which is a costly, labor-intensive operation. The plastic bottles must be ground up before they can be recycled. The metal housings, or outer boxes, for the plastic bottles can be re-used, but they are often bulky and inefficient to transport when empty.
Although steel drums may provide easier access for cleaning for re-use, their weight and tendency to corrode are detractors. Today, most drums are designed to be used once, then discarded. A current reported estimate of the cost of handling and disposing of a fifty-five (55) gallon drum is forty (40) to fifty (50) dollars (U.S.). Also, drums generally cannot be shipped with a dispenser valve in place; it prevents stacking So the valve has to be installed in the drum's bunghole by the customer. Then, if the valve is a gravity flow valve, the drum must be turned on its side and secured with blocks or laid in a cradle to keep it from rolling.
Another common problem with bulk containers is a tendency not to drain completely, leaving as much as seven (7) to eight (8) percent of their contents in the bottom.
A drawback with blow-molded bottles is their tendency to leak at the connection between the bottle and the dispenser valve's neck. The neck typically is sonically welded to the bottle. When the bottle is full, the connection is under substantial stress. A minor bumping of the dispenser valve can rupture the weld.
There is a need, therefore, for a transportable bulk container that is lighter than a comparable size steel drum, is corrosion resistant, drains completely, is stackable even when full, can easily be cleaned out, is reusable, can be efficiently transported when empty, and can be fitted with a gravity flow dispenser valve that will resist damage during transportation o the filled container. The container of the present invention satisfies these needs.